1. Field of the Invention
The invention relates to a thin film transistor (TFT) device, and in particular to a multi-gate TFT device having light-shielding layers for an active matrix flat panel display (FPD).
2. Description of the Related Art
The demand for active-matrix flat panel displays, such as an active matrix liquid crystal display (AMLCD), has increased rapidly in recent years. AMLCDs typically employ thin film transistor (TFT) devices as pixel and driving circuit switching elements which are classified as amorphous silicon (a-Si) TFTs and polysilicon TFTs according to the materials used as an active layer.
Such a TFT device typically includes a gate electrode and an active layer having a channel region, a source region, and a drain region and has been used as an element applying a voltage responsive to image information to a pixel electrode. However, when the TFT device in the pixel region is operated in an OFF state and the light (e.g., the backlight) impinges on the active layer, electron-hole pairs may be created in the active layer so as to generate photo leakage current (i.e., light-induced off-current), such that the image quality of the active-matrix flat panel display is reduced.